Thermoplastic elastomer (TPE) is a material with intermediate properties of rubber and plastic including rubber-like flexibility at room temperature similar to vulcanized rubber, and inject-moldable properties at high temperatures similar to thermoplastic materials. By said properties, the thermoplastic elastomer is applied for various purposes requiring flexibility such as sports products, food packaging, medical devices, exterior of portable IT devices, home appliances and the like. The thermoplastic elastomer is also capable of being extruded, producing products in which the vulcanized rubber is incapable of producing, reducing manufacturing time of the products, and recycling for solving environmental contamination problems of the vulcanized rubber.
However the thermoplastic elastomer has extremely poor matter properties including permanent elongation and extension rate (tension set) at high temperatures in surface hardness less than 40 A (shore A) compare to the vulcanized rubber, and has a limit on the application for products.
Specifically, as an example, the thermoplastic elastomer for a diaphragm of a washing machine combines with a tube assembly of the washing machine, seals with a door glass panel, and requires the low hardness with the surface hardness of 50A (shore A) or less for securing the vibration absorption and a buffering function of the tube assembly and sealability after closing a door. Also, physical properties including permanent elongation and extension rate and tension strength at high temperatures have to be secured at high temperatures for unique functions of the washing machine for drying and steaming laundries.
For solving said subjects, users have tried to produce a material obtained by alloying the thermoplastic elastomer with another resin but the obtained material does not fulfill the thermal properties required at high temperatures and instead, lose the surface flexibility which is an existing advantage.
In the US Patent Publication No. 2005-0288393, a thermoplastic elastomer composition comprising a thermoplastic resin, a block copolymer, a core-shell copolymer, and oil is disclosed. However the composition has the surface hardness greater than 70 A (shore A) and is unsuitable for applying to electric and electronic parts, especially a diaphragm for the washing machine.
In the US Patent Publication No. 2004-0151933, a thermoplastic elastomer composition comprising a thermoplastic resin, a rubber elastomer, a saturated elastomer, and oil is disclosed, but the thermoplastic elastomer composition is incapable of maintaining the surface hardness in the range 40 A (shore A) or less and has a limit on usability.
Accordingly, the present inventors have developed a thermoplastic elastomer composition which has excellent physical properties and is capable of being applied to the production of various molded articles including electric and electronic parts and vehicle parts and requiring flexibility by having excellent physical properties at room temperature and high temperatures. The thermoplastic elastomer composition is obtained by combining: a block terpolymer of an aromatic vinyl compound and alkene or a conjugated diene-based compound; paraffin oil; a polyolefin-based resin; an inorganic additive; and a polyphenylene ether-based resin for solving said problems.